Homology modeling deduced 3D structure of the Cry1Ab22 toxin

Abstract

δ-Endotoxin Cry1Ab22 is produced by Bacillus thuringiensis BtS2491Ab. The toxic spectrum of this protein is reported to span Lepidopteron and Dipteran. Here, we predict the theoretical structural model of newly reported Cry1Ab22 toxin by homology modeling method on the structure of the Cry1Aa toxin. Proposed model resembles the target by sharing common three dimensional, three domain structure. The main differences being located in the length of loops, absence of helixes (α7b, α10a, α10b, α11a) and presence of additional components (β21, α9b). Few of the components like α9a, α9b and α12a are positioned spatially at different locations. A better understanding of the 3D structure will be helpful in designing the domain swapping and mutagenesis experiments aimed at improving toxicity, and will lead to a deeper understanding of the common mechanism of toxins.